84 lines
3 KiB
Markdown
84 lines
3 KiB
Markdown
`umockdev` Tests
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================
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`umockdev` tests use fingerprint devices mocked by [`umockdev`
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toolchain][umockdev].
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This document describes how to create a 'capture' test: a test that
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captures a picture of a fingerprint from the device (mocked by
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`umockdev`) and compares it with the standard one.
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Other kinds of `umockdev` tests can be created in a similar manner. For
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match-on-chip devices you would instead create a test specific `custom.py`
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script, capture it and store the capture to `custom.pcapng`.
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'Capture' Test Creation
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-----------------------
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A new 'capture' test is created by means of `capture.py` script:
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1. Create (if needed) a directory for the driver under `tests`
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directory:
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`mkdir DRIVER`
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Note that the name must be the exact name of the libfprint driver,
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or the exact name of the driver followed by a `-` and a unique identifier
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of your choosing.
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2. Prepare your execution environment.
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In the next step a working and up to date libfprint is needed. This can be
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achieved by installing it into your system. Alternatively, you can set
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the following environment variables to run a local build:
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- `export LD_PRELOAD=<meson-build-dir>/libfprint/libfprint-2.so`
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- `export GI_TYPELIB_PATH=<meson-build-dir>/libfprint`
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Also, sometimes the driver must be adapted to the emulated environment
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(mainly if it uses random numbers, see `synaptics.c` for an example).
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Set the following environment variable to enable this adaptation:
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- `export FP_DEVICE_EMULATION=1`
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Run the next steps in the same terminal.
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3. Find the real USB fingerprint device with `lsusb`, e.g.:
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`Bus 001 Device 005: ID 138a:0090 Validity Sensors, Inc. VFS7500 Touch Fingerprint Sensor`
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The following USB device is used in the example above:
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`/dev/bus/usb/001/005`.
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For the following commands, it is assumed that the user that's
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running the commands has full access to the device node, whether
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by running the commands as `root`, or changing the permissions for
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that device node.
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4. Record information about this device:
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`umockdev-record /dev/bus/usb/001/005 > DRIVER/device`
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5. Record interaction of `capture.py` (or other test) with the device. To do
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so, start wireshark and record `usbmonX` (where X is the bus number). Then
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run the test script:
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`python3 ./capture.py DRIVER/capture.png`
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Save the wireshark recording as `capture.pcapng`. The command will create
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`capture.png`.
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6. Add driver's name to `drivers_tests` in the `meson.build`.
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7. Check whether everything works as expected.
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**Note.** To avoid submitting a real fingerprint, the side of finger,
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arm, or anything else producing an image with the device can be used.
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Possible Issues
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---------------
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Other changes may be needed to get everything working. For example the
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`elan` driver relies on a timeout that is not reported correctly. In
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this case the driver works around it by interpreting the protocol
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error differently in the virtual environment (by means of
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`FP_DEVICE_EMULATION` environment variable).
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[umockdev]: https://github.com/martinpitt/umockdev
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